| 摘要 |
A power line fault indicating system adapted to be connected in parallel with an electrical appliance for detecting the most common power line faults. The system employs a neon lamp connected in an R-C oscillator circuit which is controlled by circuitry responding to power line conditions to provide any one of three states of the lamp, namely, steady energization of the lamp, blinking of the lamp, or steady deenergization of the lamp, depending on different conditions. The circuitry includes a power supply stage, a logic stage, an averaging and delay stage, and a driver stage connected to a resistor forming part of the oscillator discharge circuit branch and arranged so as to short-circuit this resistor under normal power line circuit conditions and thereby allow the neon lamp to be steadily energized, and to remove the short circuit under certain abnormal power line conditions and thereby cause the oscillator to operate and provide blinking action of the lamp. Other abnormal power line conditions will prevent energization of the lamp. |
